Pancreatic cancer, since 2004. At first he refused treatment and said he would try "alternative medicines" and "change his diet" because that would apparently cure it. Idiotic move really. Of course we'll never know if traditional treatment would have cured him (he did get this eventually but probably too late by then), but still, I think it was stupid to refuse that. Quite remarkable he was fine for 6+ years before it started to take its toll.